1. Field of the Invention
The present invention relates to an electrostatic deflector, a lithography apparatus, and a method of manufacturing a device.
2. Description of the Related Art
With miniaturization and large-scale integration of circuit patterns in semiconductor integrated circuits, a lithography apparatus (for example, writing apparatus) which writes a pattern on a substrate with a plurality of charged particle beams (electron beams) is attracting a great deal of attention. Such a lithography apparatus includes an electrostatic deflector which deflects a plurality of charged particle beams, and is used to guide a plurality of charged particle beams to target positions on a substrate. The electrostatic deflector has a structure which sandwiches the charged particle beams using a pair of electrodes (electrode pair), and applies an electric potential difference to the electrode pair to generate an electric field between the pair of electrodes, thereby deflecting the charged particle beams.
A lithography apparatus is required to attain an overlay accuracy or precision on the order of several nanometers or less. To meet this requirement, an electrostatic deflector for guiding each charged particle beam to a target position on a substrate is necessary. An electrostatic deflector including an electrode pair located to sandwich charged particle beams, aligned in a line, of a plurality of charged particle beams has been proposed in each of International Publication No. 2010/125526 Pamphlet, and United States Patent Application Publication No. 2004/0231150.
In recent years, not only the overlay accuracy but also the throughput indicating the productivity is required to improve. Hence, a lithography apparatus improves the throughput by locating a plurality of charged particle beams at a high density. However, when a plurality of charged particle beams are located at a high density, their interval becomes narrow, thus making it difficult to locate an electrode pair to sandwich the charged particle beams.